Getting custom structure to display in Properties Window as +/- collapsable

Here's the issue. I'm experimenting with the implementation of C# UserControls. I have a structure defined which contains an enumeration and a Color struct. I would like this to appear in the property window as a +/- collapsible property, with the enumeration as a dropdown and the color invoking the typical color property chooser.

Is there a way to do this When I expose this property as read/write and public, it tells me that it is read only when I click on the property in the property window.